Litter box



FIG. 1 is a front left perspective view thereof;

FIG. 2 is a front right perspective view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a front view thereof;

FIG. 6 is a rear view thereof; and,

FIG. 7 is a right side view thereof, the left side being a mirror image thereof.

The broken lines illustrate portions of the litter box that form no part of the claimed design. 

CLAIM The ornamental design for a litter box, as shown and described. 